text:
What should I do with fuel drained from the sumps during preflighting?
What should one do when done sumping a small amount of fuel during a pre-flight?  Should it be dumped on the ramp? Or is it considered necessary to find the container far away from the airplane? Is it considered safe to dump it right back into the plane if it is uncontaminated?

I'm glad you asked this question. It never occurred to me dumping it on the ramp isn't the "right method." Honestly. That's what my instructors did.

@Jason my instructor even showed me the proper flinging technique to spread it out over a large area.  The second option was to find weeds growing in the cracks on the ramp and pour it on them to kill them.

The FAA issued an Aviation Safety Program publication called All About Fuel which talks about fuel preflight, including sumping fuel.  It contains the following:

Preflight Action     As pilot in command, you have the responsibility to determine that your aircraft is properly serviced.
  Check your aircraft before each flight and be sure you have the
  correct type of fuel. This practice may save your life! Take the time
  to inspect your aircraft thoroughly. Good preflight procedures:

Be sure all of the fuel and oil tank caps and covers are installed and secured properly after you visually check the fluid level.
Observe the color and odor of the fuel as you check the tank.
Draw a generous sample of fuel from each sump and screen drain into a transparent container. Check for the presence of water, dirt, rust
  or other contaminants. Unless you have the proper kind of fuel tester
  (e.g., GATS jar with intact fuel strainer), do not attempt to save the
  fuel drained from the sumps by pouring it back into the tank. Note: If
  you are not equipped to safely pour the drained fuel back into the
  tank, please be sure to dispose of it in accordance with EPA
  regulation.
Check that each fuel tank vent is clear of restrictions; i.e., dirt, ice, snow, bent or pinched tubes, etc.

Any FBO that sells fuel should have a way to dispose of it.  Some of them make it more obvious than others by putting sump barrels out on the ramp, but ask them what to do with it before you go out to the airplane and they should be able to help you out.  For environmental reasons, you definitely shouldn't dump it on the ground, because even if it does evaporate, it will come down somewhere.  At some airports you can even get in a lot of trouble (and have to pay a big fine) by dumping fuel on the ramp.  Don't take a chance!

Personally, I have a gas powered tug to pull/push my plane with. My tug is only certified for mogas, but I pour all of my avgas samples into it... I've never had to fuel it any other way.

Agreed. Using higher octave fuel in an engine rated for lower octane is always ok, so 100LL in a mogas 89 octane engine is fine.

@DavidWihl: Using leaded fuel in an engine rated for unleaded one is not though, because it damages the catalytic converter.

Lawn mowers don't (yet) have catalytic converters

You should dispose of it in a fuel disposal container, if your airport has them (and many states require it). Barring that, the best option is a type of fuel strainer called a GATS jar that has a built-in filter to catch any particulates. If you pull a sample in a GATS jar that comes back "dry" you just unscrew the filter and put it back in the tank.
If you pull water, you should dispose of it in a way that doesn't involve dumping it on the ground. Either put it in a disposal container (lobby your airport or FBO to install them if they don't exist) or your own labeled gas can and use it for your lawnmower or something.
If you have no other option, try to avoid pouring it in a puddle on the ground. Toss it in an arc so it covers a large area and can evaporate as quickly as possible

Used properly the GATS jars will filter out any particulates or water that got pulled in the fuel sample (they do work, but it can be tricky to get the screen soaked in avgas before pouring the sample back).

I always put it back in the tank if it's not contaminated. Even if it is I'll put as much as I can back in. A few millimeters of water is not going to do anything when it would take almost a gallon of it just to reach the fuel pickup.
As for dumping, I've heard the EPA has been known to watch airports with heavy flight activity. They'll write your tail number down and send you a fine. Some states don't have any laws about it, though. I would save all the fuel I could, honestly. You can filter out uncontaminated fuel and reuse it. I know that's not really plausible if you're not in a hangar, though.


text:
Can an orienteering compass be used in place of a protractor?
First off, please forgive me if this is a stupid question.
I was given a protractor during flight training, learnt to use it and obviously works quite well.
However, I've started using my old maps for sim use and used an orienteering compass which also works quite well
In fact, I found it easier to get bearings using the compass than the protractor.
So for my question, has a protractor always been issued and used, or do some schools prefer to use other orientation tools?

I'm not understanding how you are using the orienteering compass, could you explain more fully? Are you actually aligning the chart north with it?

@GdD No, the compass has meridian lines similar to the protractor.

From your description you are using the orienteering compass to measure course lines by aligning the side of the compass to the grid lines and using the dial to align with the course. There's no thing inherently wrong with this method, if done properly it will give you an accurate course. Personally I like the protractor better, but it is personal choice. You may have to explain what you're doing to an examiner later, I wouldn't imagine it would be disqualifying though, although you never know, some examiners are sticklers for that kind of thing.
However, before you throw away the protractor I suggest you put one hand behind your back and try to use your orienteering compass to measure a course. You see, at least in the UK you will be tested on your ability to divert, measuring a course using a map while also flying the airplane. That's where that kind of protractor comes into its own, and why I'd recommend you stick with it.

I get the true course to waypoint by lining the edge of the compass with my desired track then turn the compass dial so that meridian lines are parallel, then reading the indicated course. I'm not discarding the protractor, just found it interesting that I was easier to read bearings from

@chaos505 - You've re-invented the rotating plotter.

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text:
Is there a way to avoid exhaust fumes when landing?
I've taken a few hours towards my private pilot's license and each time we land I've smelled this plume of engine exhaust that we seem to fly/roll through just as we're touching down.  I must be sensitive to the fumes because I usually end up with a slight headache after a few minutes.  I haven't asked my instructor yet (because he may think I'm nuts) but is there any way to avoid this short of holding my breath?  I'm flying in a Cessna 152 for my training.

@SkipMiller's answer hits all the points. I'm commenting to emphasize: always ask your instructor. If you have a question that you are embarrassed to ask them, maybe you need to find a different instructor to fly with.

even a comment of "could the exhaust be leaking? I think I smell something odd here." would be enough

Thanks for the thoughtful responses.  I only smell the fumes at a single instance in the landing, so my thought was that it was just the exhaust getting carried into the fuselage at a certain point (perhaps when the main wheels are down but the nose wheel isn't, allowing exhaust from below to travel up), but I will bring it up with him and get his thoughts.

Smelling exhaust in the cockpit is not normal.  Tell your instructor and squawk the problem.  Bonus - turn it into a learning experience by arranging to be with the A&P when he decowls and inspects.  You can learn a lot about the engine that way.
If you are getting a headache from this you may have mild CO poisoning.  This does need to be checked out.

The US Centers for Disease Control and Prevention have a page about the effects of carbon monoxide poisoning. Headaches are a common symptom so you I concur with the need to get to the bottom of this, and urgently.

+1 - there are some times where you might get a whiff of exhaust in the cabin (mainly ground operations), but on landing isn't one of those times. The aircraft should also have a CO detector (either a "chemical spot" type or an electronic one) - If it doesn't you can get battery-operated detectors relatively cheaply at your local hardware store. A good piece of equipment to keep in your flight bag.

I wonder if you would get enough CO on a quick roll through on landing to get a headache. It sounds more like a crack in the heater muff that is leaking into the vent/heater system. Did you have the cabin heat on? Even whith the vent closed (heat off) it is not so airtight to keep the CO from making its way into the cabin during the entire flight. On touchdown (low airspeed) there is less air flowing through the heater muff and thus a lot higher concentration of CO possibly making it more noticable. As an A&P, Ive seen many cracked exhaust systems in the heater area.

Steve, I agree with you.  @time trap, please let us know what the mech found.

Dear Aspiring Pilot;
By all means; you have stumbled onto the most important issue of being a PIC [Pilot in Command]. You only let that happen ONCE without fully understanding
why it is happening. There are no little issues as a PIC.
Part of your pre-flight check walk around should have included pushing down on the 'nose' of the Cessna and check the condition of the shock on the nose-wheel.
I.E. leaks in hydraulic shaft, tire condition, [nails,glass?]. It also seems when you were checking the wing tanks for water and checking engine oil you would have seen a black 'smudge where the exhaust was leaking.
It is imperative that  walk around is done; It can point out little things like the fact that a '152' DOES NOT have retractable landing gear;

Not sure what tire condition has to do with exhaust smells in the cockpit. Also don't understand the importance of the 152's fixed landing gear - I expect the OP knows this... -1.

The OP said "perhaps when the main wheels are down but the nose wheel isn't", which if it has fixed gear, must mean "the main gear is on the runway, but the plane is still a bit nose-up". That would be an unusual airflow (compared to the rest of the flight), which could bring exhaust into the cockpit, perhaps through a leak somewhere.

I completely agree that you should check the exhaust system as part of your preflight checks (and that you shouldn't let a problem like this go unfixed when you notice it in flight), but it's definitely possible to miss an exhaust crack, even in a through cowling-off preflight. Some of the most deadly cracks happen under the cabin heat shrouds where you can't see them (and where the result is pumping exhaust directly into the cabin when you have the heat on).

@PhilPerry - Yea, that's what I was thinking -- the unusual airflow briefly caused exhaust to flow into the cabin, although I'm hopeful this can be remedied (as all the responses seem to be leaning towards) because I really don't like the post-flight headache.

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What happens when two different control inputs are commanded in an aircraft with two control columns?
For example, the captain starts pulling back and to the right to turn right. First officer initiates a left diving turn. What happens?

It depends on the aircraft. In any aircraft where the two control columns are linked, there's only one input to command the control surfaces. While most smaller aircraft are connected directly through the control surfaces, Boeing publicizes that on the 787 - a fly-by-wire aircraft - the control columns "[a]re cross-linked between pilots to reduce potential confusion."
On Airbus aircraft (and probably others), the controls are not linked: there is no indication on one pilot's controls of the other's position. The computer handles this by adding the two inputs: opposite commands will cancel each other out, while both pilots commanding the same input will increase the total commanded input. Some Airbus aircraft have a feature which makes an announcement of "DUAL INPUT" when there is input on both sidesticks simultaneously. As of January 30, 1997, this was "an installation" (optional feature, I believe) on the A320 and under development for the A340.
Airbus aircraft also have a Priority Takeover button, which lets one pilot take control and have the airplane ignore inputs from the other sidestick. As Farhan noted, good CRM (Crew Resource Management) is also very important to ensure that only one command is given at once.
Some aircraft have linked controls, which can be separated if necessary. On the 767, if sufficient force is applied, the elevators will "split": each control column will control one of the elevators. The pilot who is stronger or better prepared will have more control over the aircraft. There's also the EMB-145 and -135:

The roll input is ... linked at the control column[.] Each yoke independently controls its own aileron -- the CA yoke only flies the left aileron and the FO yoke the right aileron. It is only through the control column linkage that each yoke can control the whole airplane. It is done this way so that if there is a problem with a cable jamming, the control interlock can be disconnected and at least half control regained.

Also, an aural warning is heard in the cockpit if two inputs are given at the same time -- "dual input".

Another interesting example is splitting the elevators in the B767, as occurred in EgyptAir 990.

@orique is that new? I don't recall hearing about it from AF447...

@voretaq7 That made me think. I don't know if it's fitted in all airbus aircraft, but some certainly have it (http://avherald.com/h?article=41951d02/0002&opt=0) and some crews report about not hearing it: http://avherald.com/h?article=43ab3354

@orique Seems like a rather important safety feature to add if it's not installed on the entire fleet by default :)

Thanks for the suggestions, I've edited to add those two points. I found plenty of information on various fora, but no reliable source, so the 1997 report is as good as I can do for the DUAL INPUT reference. On the split rudder, I see references to 50 lbs causing the split - but nothing I'm comfortable quoting.

Averaging the inputs seems like a typical software engineer's solution. It sounds like it would have perverse consequences -- if one pilot is commanding, say, full nose-up and the other is giving a slight nose-up command, then if the latter lets go of his stick the nose will go up faster.

@HenningMakholm As an aspiring software engineer, I take offense! :)

@HCBPshenanigans: As an actual software engineer I have immunity.

@HenningMakholm I'm a software engineer and I never would have considered such a solution. It sounds like the solution of someone who knows nothing whatsoever about aviation, which is puzzling for one of the world's largest aircraft manufacturers. As far as AF447 is concerned, this was more than a small factor in that crash. It seems unlikely that the crash would have happened at all had the inputs not been averaged. Of course, the primary issues were major pilot error and lack of CRM.

Notice that hypothesis of double control issue on Airbus was driven by Nick Ross, a journalist not involved in the investigation. This is not part of the conclusion of the official investigation report, so it is opinion based.

Hmm, funny how things like that sneak into "common knowledge". I always thought that was the case, but the accident report doesn't mention it at all. Thanks for the correction; I'll update the answer.

do you have a source for averaging inputs on the airbus?

@HenningMakholm As a computer scientist, I don't think averages work that way: (1+0.2)/2 = 0.6, but (1+0)/2 = 0.5.  The second pilot releasing his stick would reduce the average nose-up input.

@JeffreyBosboom i think this is only in the case of dual input.  with single input, only the one input is considered; no need for averaging.  so (1+0.2)/2 = 0.6, and (1[+0])/1 = 1.

@JeffreyBosboom: Note that most of the above comments were written when the answer read: "When both sidesticks are commanding an input, the airplane averages the two", which looked like it implied no averaging is done when one of the sticks is in neutral position.

In the case of 727-100 and 747-100 and -200 aircraft, if both pilots were exerting opposite forces on the control column, the stronger pilot would win. In these aircraft the control columns are linked by heavy duty cables or rods. I don't believe it would be possible for human strength to break them.
The cabling feeds into hydraulic valves, which use hydraulic pressure to move the control surfaces. However, the 727-100 has manual reversion, which enables the pilots to move the control surfaces by the cabling alone should all hydraulic pressure be lost. We used to practice this in the simulator. When flaring for the landing both pilots would work together to move the elevator.

Man you guys must have arms like popeye to do that.

@BurhanKhalid Ha, ha, not really. My guess is that average pilot strength is less than that of, say, the average construction worker or many manual labor jobs. The manual reversion was on the 727, not the 747.

I remember doing a control wheel check on the 727 during maintenance where the control wheels where turned in the opposite directions. There was a clutch that disengaged the control wheels from each other, so that the ailerons could be controlled if one side jammed. But I can't remember how one side had priority over the other side. In the case of the elevator, the stronger pilot wins because both sides were directly connected.

@Eric Good catch! I had forgotten about that aileron arrangement, and I still can't remember if one side has priority over the other somehow. Perhaps, though, two pilots fighting over opposing aileron input is sufficiently different from a jam that the mechanism would still let the stronger pilot win? I haven't the slightest idea.

In an airplane when two pilots are actively sitting on the controls, only one is actually flying the airplane. The other is normally watching over the actions of the pilot flying the airplane. Hence the terms are:

Pilot Flying (PF)
Pilot Not Flying (PNF) or Pilot Monitoring (PM)

They can switch the responsibility of actual flying at will, or if the captain orders as he/she is the legal commander and always responsible for the aircraft. From Wikipedia:

Even when the first officer is the flying pilot, however, the captain
  remains ultimately responsible for the aircraft, its passengers, and
  the crew. In typical day-to-day operations, the essential job tasks
  remain fairly equal.

When the pilots want to switch the responsibility of flying, they exercise the routine known as Positive Exchange of Flight Controls. This can be performed as following:
PF: You have the controls or Your plane
PNF: I have the controls or My plane
PF: You have the controls or Your plane

or
PNF: I have the controls or My plane
PF: You have the controls or Your plane
PNF: I have the controls or My plane

I've read some people doing the first two lines only, although it is not the standard way.

If you are referring to the fact that both pilots are actually applying contradicting control inputs, then obviously it is not a good thing. It can break the control surface, or the cables connecting them (no in case of fly-by-wire) or even can get very deadly.

I think it's just the latter part. The rest of the answer seems mostly irrelevant

The captain starts pulling back and to the right to turn right. First officer initiates a left diving turn. What happens?

It depends.

Linked controls
On some aircraft, the main controls are linked, often mechanically.
So the strongest pilot, or the one with most stamina, wins.
There may potentially be a period of alternating sudden strong deflections of the control surfaces as the two pilots fight for control.
Independent controls
On some aircraft, the main controls are not linked.
There will usually be visual, audible and sometimes tactile indications to both pilots of a conflict, if both pilots are making inputs.
Either pilot can typically press a priority switch to gain control and cause the other pilot's inputs to be ignored.
There may potentially be a period where conflicting pilots are alternately pressing their priority switches.
Column vs sidestick
Either the traditional control-columns or modern sidesticks can, in principle be designed for either linked or independent operation. It happens that there are two major makers who have historically taken different choices for both these aspects but it is possible to have linked-sidesticks or independent-columns.
Airbus
The operation of the priority switch is shown in a video
A slightly longer video shows how conflicting inputs are acted on and indicated.
The following text was coughed up by the intertubes and appears to be a description of Airbus sidestick operation.

5.2. Dual input detection enhancements
5.2.1. Description As a complement to the active sidestick evaluations, various new features have been developed to improve the
  crew awareness of dual input situations on the FBW aircraft. The main
  objective of these features is to provide warnings which will prevent
  long duration dual input situations. The following visual, aural and
  tactile cues have been tested with the active participation of pilots
  from Airbus, airlines (Cathay, DLH, Sabena), unions (ALPA, SNPL,
  German Cockpit) and Airworthiness Authorities (CEV, CAA, FAA,
  Transport Canada).
VISUAL CUE
When both sidesticks are deflected simultaneously (for more than 0.5
  sec), the CAPT and F/O captions of the Sidestick Priority Light on
  both glareshields are illuminated flashing in green. As soon as the
  priority p/b is pressed on either sidestick, the glareshield lights
  revert to the classical priority configuration (CAPT and arrow or F/O
  and arrow). The principles of this visual indicator are identical for
  all FBW aircraft.
AURAL CUE
A "DUAL INPUT" audio message is triggered when both sidesticks have
  been simultaneously deflected for a certain time. The timing of the
  audio message has been adapted on the A320/A321/A31 and A330/A340
  families due to the different systems architecture such that, on all
  cases, the message is triggered after the illumination of the
  glareshield lights. In this way, there is a degree of sequencing such
  that the aural warning will only be triggered if the dual input
  situation is prolonged. The "DUAL INPUT" audio is repeated every 5
  sec. It has the lowest priority of all the audio (voice) messages but
  can be generated simultaneously with any other non-voice audio
  warnings. When the priority p/b is pressed on either sidestick the
  warning is canceled except if it has already started (i.e. it cannot
  be interrupted).
TACTILE CUE (BUZZER)
The sidestick is fitted with a small electrical motor which rotates an
  unbalanced weight and thus generates a vibration of the sidestick. The
  level of vibration depends on the rotation speed and on the weight of
  the rotating mass. When both sidesticks are deflected for a certain
  time, the buzzer on both sidesticks are activated to produce a series
  of intermittent vibrations. Since the level of buzzer vibration could
  not be increased at will due to various reasons (e.g. rattling noise
  on the lateral console) the principle of intermittent "shots" was
  selected to improve the detection of the buzzer activation. The timing
  of the buzzer activation has been adapted on all the FBW aircraft such
  that the buzzer is activated simultaneously or slightly after the
  illumination of the glareshield lights. When the priority p/b is
  pressed on either sidestick the buzzer is stopped immediately.

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What is the business purpose of scheduling two separate flights on the very same route with 5-10 minutes separation?
As in question. I have noticed, for example, that Berlin-Tegel has TXL-CDG route served by both AirBerlin and AirFrance with exactly five minutes separation. First plane takes off at 09:50 and second one at 09:55. I have also noticed that the same rule goes for longer routes, i.e. LHR-SYD goes with around 20-40 minutes separation, served by both Qantas and British Airways.
Can someone explain me a business or economic reason for doing so?
Why these two planes are not scheduled with a bigger separation? I.e. 2-3 hours or even half of day in case of long routes? Wouldn't that assure bigger chance or getting more customers? If route interest is big enough that two planes, near each other, needs to be scheduled, then why simply one airline don't use a larger airplane and the other one schedules its own flight 2-3 hours later or so to capture "other part of day" travellers?

TXL-CDG is not the best example since there's a flight every 1-2h. But this is also often done when there are only very few flights a day.

Different airlines are not working together to provide the best coverage, they are competing.

@sweber As for the schedule, I saw yesterday, I would say that these two were the only two planes on this route for 08:00-16:00 part of the day. So, five minutes separation for the only two planes for half day on given route does sound like a good example, as for me.

@J.Hougaard Still... competing should mean gathering as much customers as possible, yes. I can't understand business reasons for operations as described in question. IMHO I'd be more reluctant in picking airline A or B if they'd give me option to either fly in the morning or to fly in the evening rather than to fly at 10:00 or to fly at 10:10.

This is a prime example of Hotelling's law.

@Sanchises Sounds like a good answer.

If you look at just the schedules it says nothing. If you look at the prices you can see that Air Berlin was pricing the flight significantly lower than Air France. As was stated above, it was competition.
Unfortunately, things did not end well for Air Berlin. The airline declared bankruptcy in August 2017, and was unable to obtain further funds from its primary shareholder, Etihad. The company closed its doors in October of the same year.

I'm not convinced by the utility of your addition to your answer. Is it necessary to answer the question?

I think the edit adds interesting context.

The question was about "business or economic reason." The additional infomation specifically relates to that. "Necessary" is not an appropriate filter to judge answers in all cases.

@Federico: Answering the question is, generally, encouraged. ;-P


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How to match ATC requirements to work in EU?
My Brazilian boyfriend is finally planning to move into the EU zone (he actually got an Italian passport). He would be glad to keep his work as an Air Traffic Controller but despite his 10 years working experience he told me he should start the training all over again.
Can someone point us out the shortest way to match the requirements for EU Standards and/or suggest us where to find this kind of information?

I edited the title to be more specific. If it does not reflect what you meant, feel free to edit it again (and to edit the description of your question as well to be more specific)

Thank you very much, I appreciate it

I would suggest to contact the IT ANSP and ask if they accept applications for ready entry ATCOS: https://www.enav.it/sites/public/en/LavoraConNoi/Traduzione-di-Contatti-n.html
In Germany we have plenty of so called „ready entries“ who applied for a job as ATC in Germany while holding a valid non-EU ATCO license.
After an assesment by our company and - hopefully - signing the contract they participate in some weeks of sim training to learn the procedures of the new sectors. After succesfully completing the sim phase the OJT (on the job training) begins. During something between 6 and 12 months they will train working in real world with a coach and finally take one examination per working position.
That‘s it!

Thank you so much for your answer. We'll surely follow your suggestion!


text:
Why are the Phugoid and Short period approximated instead of calculated exactly?
We can calculate the period and half-amplitude time for phugoid and short period using equations of motion. We will get an exact answer.
Then why is there a need for doing approximations to equations of motion for calculating period and half-amplitude time for both motions?

Hello Pavankumar Koratikere, welcome to aviation.stackexchange. I've rephased the title of your question into an actual question, which is the standard here.

By approximations, I believe you mean the following (found in any major stability & control textbook and this MIT course note), where the $_0$ notation stands for undisturbed trim condition:

Short-Period damping:

$$\zeta_{sp}\approx-\frac{M_q}{2}\sqrt{-\frac{1}{V_0M_wI_{yy}}}$$

Short-Period frequency:

$$\omega_{sp}\approx\sqrt{-\frac{V_0M_w}{I_{yy}}}$$

Phugoid damping:

$$\zeta_{p}\approx\frac{1}{\sqrt{2}}\frac{C_{D_0}}{C_{L_0}}$$

Phugoid frequency:

$$\omega_{p}\approx\sqrt{2}\frac{g}{V_0}$$
They are useful because:

They are computationally easy, and offer first approximation during early conceptual design and rapid iterations. However, in the 21st century, that's not saying too much.
They offer important design insight to engineers. It's not enough to calculate the modes; more important is to understand how to change the aircraft design such that the modes are adequate. With the full linearized matrix, it's hard to appreciate how derivatives influence these results (certainly for me). Now when you look at these simpler equations, the effects are almost intuitive! For this reason, these approximations (especially the lateral/directional approximations) will never go out of fashion.

On another note, since aerodynamics, especially transonic aerodynamics, propulsion and the equations of motions are inherently nonlinear, the linearized matrix (and the concept of eigenmodes) is itself an approximation.

That last paragraph is indeed very important. All mathematical models are approximations. The only way to get to the exact period and half-amplitude time is to measure it in flight.


text:
When ATC uses distances, are they using nautical miles or statute miles?
"Skyhawk 872ND, airport at your 12 o'clock in 15 miles."
"Baron 981K, traffic, 2 o'clock 5 miles, opposite direction, a Piper southbound, 1000 feet below you."
Does ATC use nautical miles or statute miles?

Related

ATC uses nautical miles, this is because it's the ICAO standard documented in Annex 5 - Units of Measurement to be used in Air and Ground Operations, which states that Nautical Miles are to be used for distance and Knots for speed as an alternative non-SI measurement. Kilometers are actually the primary distance measurement because they are the SI standard, however nautical miles are so entrenched they've kept them and there's no termination date.
The ICAO annex is hard to find because everyone wants you to buy it, however the standards have been copied into this CAAS document word for word if you want some light bedtime reading.

Broadcast weather METARs use statute miles. Navigational information, such as that from ATC, would use nautical miles.
Nautical miles are used for navigation, mainly because a nautical mile is one minute of a degree on the surface of Earth's geoid.(basically one minute of latitude.)
Kilometers and statute miles are each a fixed distance unit, nautical miles are not a fixed straight line distance but are a fixed fraction of the earth's circumference. Very useful for long range navigation and triangulation, 60 miles to each degree and exactly 21600 nautical miles per circumnavigation.

I don't think the nautical mile is defined the way you're talking about anymore.  It's exactly 1852 meters nowadays.

METARs don't use statute miles everywhere, internationally it's usually kilometers. In any case if it's statute miles it says SM after.

You're right @ErinAnne, Annex 5 specifies exactly that.

The question was about statute miles vs nautical miles, clearly Km are Km, at every station that uses miles the METAR uses statute miles, the station is considered a 5 statute mile radius, the "vicinity" is 10 statute miles, and up to 30 statute miles for "distant".(DSNT is only found in remarks section)
The one exception is for lightening which uses NM, though I don't know why. And wind speed is in knots, because aircraft speed is generally in knots.

The meter originally was the same concept as the NM. It was originally defined as 100 km per gradian latitude, the gradian being the original metric unit of angle. In both cases, it was realized the Earth is not a sphere and the measurements kept being refined anyway, so they were decoupled.

The NM was not defined as a strict linear distance, the meter was. The difference is the NM lends its self to positional navigation on a sphere, -finding accurate locations on the geoid regardless of changes in shape, size, or local distortion(mountains). Linear distance units have limited value in this due to curvature and distortions, they require substantially more initial computation, lack the accuracy of integer fractions, and all the data must be recomputed and adjusted for relatively minor changes in earths shape. The angular NM can be used equally on any planet using the same tables.

@Max, even if it was true (I doubt, although it may be partly), it is not anymore. NM is considered a fixed unit of distance (and ultimately defined via SI, as everything nowadays).

It is true, currently, if anybody uses the NM in that fashion and I know sailors who do use it in that fashion. A fiat declaration in a book some place does not magically change maths and metrology, no more or less than that town that attempted to declare Pi=3.2 exact. 1852meters is just 1852 meters, in this form it is a close enough approximation for estimating speed in knots but of little use otherwise.

What, it is the definition! Units of measurements change their definitins uite often. There was a revisiin of the SI ystem this decade. They units did change then and ven the value of certain physical constants can change that way. Pi id not defined by its value, but many uinits are defined using otherr units.

The SI units themselves don't change they are only refined to a more accurate description.

Dictionaries have allowance for multiple definitions under a single word for a reason. Just consider pumpkins and tomatoes, they are defined as vegetables by most statutes and treated as vegetables in cooking, but botanists define them as berries. One word two definitions.

authors: Vladimir F Героям слава


text:
Can an increased current rating of a Ground Power Unit damage an aircraft?
Assuming you are working on an Aircraft, where the Ground Power Unit (GPU) is rated at 28V DC with max. 1000 amperes. What is the danger involved if your are to increase the current rating of the GPU to 1200 amps?

Are you talking about increasing the load current or the GPU current rating?

Your question is unclear. "Increase the Amperage to 1200" could mean more than one thing. Do you mean increase the load to the external power? Increase the capacity of the external power? Or ??

@Sanchises I meant The GPU current rating ..to increased from 1000 Amperage which is the Aircraft Amperage rating ......to 1200 Amperage which is more than the required current ,voltage remains the same. ( 28VDc )

@JuanJimenez what I mean the Aircraft specs says  the   External power is 28VDC,1000 Amperage ,,, now take this scenario...someone ignorantly tempered with the GPU Amperage increase it to 1200 Amperage...now you want to power the Aircraft... assuming you were not aware the GPU Amperage was above limit....in that case what damage could possibly be ? Thank you.

No damage, as per my answer

@Waziri You can't "tamper with the GPU Amperage" like that. Amps are what the destination of the power draws from the GPU./  What the sign is saying is that the GPU must be able to provide at least 1000 amps.

@JuanJimenez thank you sir

I find the easiest way to think about Volts and Amps is that the voltage is "pushed" and the amps are "pulled".
This is the same with pretty much any kind of power supply, whether we're talking mobile phones or planes.
To that end, the voltage requirement always needs to match. If your device is expecting 28Volts in DC then your power supply MUST provide 28Volts in DC - anything else is likely to damage it, could cause a danger and almost certainly won't work.
But current (Amps) is different - your power supply needs to meet or exceed the current demands. So if your device can pull up to 1000 Amps, the power supply MUST be able to provide 1000 Amps or more.
So, to answer your two possible questions. You can increase the Power Supply (GPU) to a 1200 Amp model (or beyond) with no ill effects, but your device (The aircraft) must have a current demand that meets or is less than that.

I agree. No damage from having an external power supply capable of handling more load than the aircraft can create. What the placard is saying is that any external power supply must be able to handle at least a 1k ampere load.

Hello I have another question pls

Good afternoon sir

Pls i am installing a new GTN 650 with an External CDI (HSI KP1 552 ) everything seems to be normal before connecting the GTN ,,after connecting the GTN my NAV fla g stays it doesn’t Go OFF

And if i disconnects the GTN from power My HSI behaves fine


text:
Whats the difference between a paragliding rescue chute and a parachute?
Whats the difference betweem a paragliding rescue chute and a parachute and could I use a parachute as a paragliding rescue chute and what would be a disadvantage/advantage?
At least these points are imortant: Stablity, descent rate, manoeuvrability, opening speed, reliablity.
I'm asking because I've found articles (in german) which make the argument that the current rescue systems for paragliders are a mistake and that "BASE systems" are starting to beeing used in the acro scene. However I could not find details.

dhv.de -> Rettungsgeräte
x-dreamfly.ch -> Retterproblematik

Paragliding rescue chutes are typicly round canopies but there are also other special forms.

Military troop parachutes are also round canopies.

So are chutes used for space exploration.

While parachutes are rectangular.

And also paragliders are rectangular.

Round canopies are said to have a slower descent rate, are more stable then other forms, are simple and open faster and are small but they are not feasible to manoeuvre but I could not find references to back up those claims.

Paragliding chutes (and the rectangular chute) have a distinct feature, they move forward. Circular chutes have limited maneuverability in that they can turn a little bit, but they are mostly at the mercy of the wind and drop (relatively) straight down. Which one you need depends on what you need it to do, if you need to glide/steer to a specific landing area you need a "gliding chute", if you just want to cushion the touch down, a circular one is fine.

@RonBeyer Thanks for your comment. I've heard that paragliding rescue chutes can't handle opening loads as big as parachutes. If one would cut he's paraglider and reaches terminal velocity a paragliding rescue chute would tear itself apart when opening. Do you know something about this issue?

@NtFreX  I don't think the paraglider reserve would tear itself apart, I think the weaker paraglider reserve lines would exceed their breaking strain and would snap

and open faster I doubt that. Round canopies generally have a larger volume. If that is not a clue that it takes longer to open then I don't know what. Round canopies have less room for changing the opening speed, where as a square BASE canopy has loads of ways to speed up the opening process.

Paragliders are not rectangular in the way that skydiving canopies are. There is a very noticeable taper towards the wingtips.

I think you need to be more specific. Skydiving reserves can be round or square and paragliding reserves, as you not, come in several different shapes. Furthermore, it depends what sort of deployment you are concerned about as well as risks such as downplaning.

Drawbacks of a skydiving emergency reserve parachute compared to a paragliding emergency parachute would likely include excess bulk and weight, and possibly a longer time to complete the opening sequence-- though perhaps the latter point would not apply to a parachute intended for BASE jumping.  If one has room for the skydiving emergency reserve parachute in their harness, and one is engaged in a high-risk style of flying such as aerobatics, it might make some sense to consider flying with it rather than a purpose-designed paragliding emergency parachute.
For more see related answer Can a paraglider rescue chute and its pilot handle terminal velocity?
It sounds like you have a more than merely academic interest in this topic; if so I'm sure you'll do further research, and we'll look forward to seeing a detailed self-answer to one or both of these questions in the future.

Am I right in thinking that a skydiving reserve relies on airflow to deploy, whereas a paragliding reserve is thrown by the pilot and this action inflates the canopy?

No the paraglider reserve deployment is very similar to the old "throw out" reserves that were used during the round parachute skydiving days.  Those reserves were thrown out (from a chest pack) while still connected to the main following a malfunction, then the main was cut away.  They didn't use a pilot chute because the jumper did the extraction by hand, but were still inflated by the airflow.  Paraglider reserves are more or less deployed the same way except you just grab the container and toss it and airflow does the rest.

@John K  - Thanks for that, the only time I've thrown a paraglider reserve is at a repack.  I don't know anything about skydiving reserves.  Or hangie reserves for that matter

@DaveGremlin most skydiving reserves have a spring-loaded pilot chute. So they are firstly relying on the spring to deploy then the airflow catching the pilot chute.


text:
What happened to Widereøe flight WF0597?
WF0597 was a scheduled flight from Bergen Airport Flesland (ENBR) to Kristiansand Kjevik (ENCN). The Embraer E190-E2 immediately started circling Flesland and continued for about 1 hour and 40 minutes, before making a stop at Flesland.
What could have happened to this flight such that it would behave as it did?

The aircraft never changed its squawk, indicating that it did not file an emergency.
Multiple aircraft landed while WF0597 was circling, including an E190-E2 also operated by Widerøe, indicating that nothing was wrong with systems/runway at Flesland.

A pilot friend suggested landing rounds, but this means that the flight was cancelled at some point, even though the websites of Widerøe and Flesland says it had departed as scheduled.
Is this normal? If not, any theories as to what might have happened?

Your screenshot shows the path for flight WF9480. Flightradar24 shows 2 occurrences of such flight one on the 5th August and one on the 6th August, both are training flights for landing practice. From your screenshot, you were looking at the 6th August flight.

All occurrences of WF597 show an aircraft regularly departing Bergen and landing in Kristiansand. All have been operated by a Dash-8, none by an Embraer.

You have probably mixed up two aircraft that were close in the air.


text:
Can rotorcraft pick up a dangerous electric charge?
So, I was re-watching The Hunt For Red October, (in light of current Russian shenanigans with Sweden), and there was a scene in which a crew-member on the ground was electrocuted by making contact (and presumably grounding) the helicopter, which had picked up a charge in the stormy weather. Can anyone explain more of what is going on here?

I realize that this is a decade-old question, but here is a video of a work crew replacing a TV antenna with the help of a helicopter, and you can see at 15:24 in the video that the guy with the grounding hook forgets to use it, touches the new antenna with his hand, and gets a painful shock from it despite his work gloves.

In the same way than an aircraft will build static charge on the wings from friction with the air, the same thing can happen with helicopters from fast moving blades.
From a 1962 US Army document:

Any aircraft flying in the atmosphere can be considered as a conductive body located in a highly electrically insulated environment. In such a body, electrostatic charge is generated by three principal mechanisms:

Charge transfer created by a triboelectric effect between the aircraft and the atmospheric particles, such as dust, water, water vapor, snow, etc.
Unbalance of the ionic content of the exhaust gases produced by the aircraft engine(s).
Induction charge due to high electrostatic
field gradients which are found occasionally in the aircraft flight path.

Source

Here's a more detailed photo of the US army discharging a helicopter while wearing insulating gloves:

 SGT Nathan Rodeheaven uses a static probe to discharge static electricity from a UH-60 Black Hawk before his teammate, PV2 Danny Browning, hooks up the cargo to the helicopter. The safety measure prevents the hook-up man from being electrocuted in the event there is accumulated static electricity. Photo: Kristin Molinaro

"This effect is also amplified by moisture in the air" - Isn't it generally the opposite? Higher humidity = lower resistance to ground = less static build-up.

Also check out videos of workers being lifted to high voltage power lines by helicopter. In that video they energize the helicopter to the 500kV line voltage so they can work safely (there are some 765kV videos too). See also this question and this article. Although I'm not sure how interesting my comment is, since I don't really know what they do when they land...

@AndrewMedico The moisture contributes charge just like the air does, see P-static.

Many amateur radio operators are familiar with "rain static", a.k.a. precipitation static, which is radio noise resulting from a voltage gradient in the air caused by rain and cloud droplets interacting with each other.

This static takes the audible form of a sizzling noise that can elevate in intensity and pitch from a slow hissing, popping, noise to a whining musical noise that increases in pitch.  When lightning flashes, even in the distance, the noise often stops. The noise then restarts, rapidly building to high pitches or high levels.

@JasonC According to the video description, those are AC power lines with a phase-to-ground voltage of 288,600 volts. That means that the peak voltage relative to ground is about 400,000, which means that that helicopter is charged up to 400,000 V, then discharged down to 0 V, then charged down to -400,000 V, and then discharged back up to 0 V, all fifty times a second! If my back-of-the-envelope calculations are correct, a person touching that helicopter would probably be able to feel it, but would not be injured. (A person touching that helicopter and the ground would be killed.)

I am a Naval Aviator and as part of my water survival training, I was deposited by boat off the coast of Florida and picked up by helicopter.  It was a huge point of emphasis that we let the helicopter's rescue hook touch the water to discharge any built up static before we touched it.
No one in my class grabbed it before it hit the water, so I can't speak to how bad the shock would have been.

what do you fly?

I just retired.  I flew and instructed in the P-3A/B/C, EP-3E, and the T-6A.

I work for a Christmas tree farm and we harvest our trees out  of the field using a helicopter. I am the hook man and attach the bundle of trees to the heli, then he takes them to another location. In that breif trip during a rain storm, or even a foggy day static charge will build resulting in a very unpleasant shock. Sometimes bad enough it will contract the muscles in my hand and arm. I’ve been doing this for 3 years and finally invested in some 20,000Vac insulated gloves that are enough to keep this from happening.

Helicopters in normal weather will build up a static charge, just ask any ground crew for a logging helicopter. Normally the hook will be grounded by dropping it on the ground before the hooker will touch it.
Or a grounding rod will be used to neutralize the static charge.

I was struck in the forehead in 1983 from the discharge off a CH-53. I was wearing a kelvar helmet which was split down the middle from the strike, heart rate slowed down to 4 beats a minute thought I was a gone. I was stationed at camp Pendleton USMC when it happened.

I'm sorry, but I can't help being highly skeptical about your remark about "4 bpms" (and a split helmet). Moreover, while this story might answer positively to the title question, it does not address the request for explanation of the phenomena.

Frederico would like to share more info with you but new to this site is the some way I could talk to you I have read a lot of the studies just need more info and you sound like you have the knowledge Imlooking for

@Federico just gonna say that getting hit in the head with the cargo hook such that it cracks the cranial (or helmet) is not beyond belief: depends on how it was swinging, etc. (Part of why one wears head protection on the flight line in the military)  The cargo hook is made of metal and the hover altitude of the CH-53E is high enough for a significant pendulum effect to build up.  (draw a mental picture of a two pound weight on a 60' rope, swinging, and hitting your  head ...)  As to the heart rate, no comment.

Yes they do. I was involved in many HDSs (Helicopter Delivery Service) and would earth the Helo with a sheperds crook and trailing copper linkage - often getting a visible spark. I also took part in the rescue of a few dozen (memory fades on how many) crew from a bombed ship with no hook and earthed the helo myself - yes it hurt.

We didn’t have a static hook in my day. I will tell you, sometimes the pilots would relieve the static charge by grounding the aircraft themselves. Sometimes, they did not. The static charge would vary From moderate to severe. And, it could even be felt by your partner who was bracing you by the legs. After the first couple of volunteer troopers started flinching from the shock and throwing the hook, me and my buddy got elected/volunteered to do it. We airmobiled the entire battery-sized unit, alternating back-and-forth as hook up man. By the time it was done, we were completely spent LOL.  82nd ABN 2/321 ,B /3-319 1986-89.

Thank you for your service.

See, CAA CAP 426, Helicopter External Load Operations, April 2006
6.25 Electrical Static Charges and 6.26 Dissipation of Static Electricity and Appendix B Static Electricity Charging Conditions

Welcome to aviation.SE! This is a useful reference but by itself it doesn't answer the question; we strongly prefer it when you summarize the key points here so that we have a complete, standalone answer.

It sounds like the helicopter had no static dissipators/wicks fitted (or broken ones!), and this resulted in the normal in-flight charge buildup zapping the groundman on the submarine instead.
I'm surprised the helicopter pilots didn't notice that awful noise in their radios well before this became a problem, though!
See What are these things hanging off the trailing edge of the wing? for more details.

The static wicks are not a magic instrument that would eliminate the static buildup. Air is pretty good insulator and the static wicks can't change that.


text:
How did the USS Vincennes misidentify an Airbus aircraft?
Wikipedia indicates that the USS Vincennes misidentified Iran Air Flight 655:

Crucially, Vincennes misidentified an Iran Air Airbus A300 civilian
  airliner, Iran Air Flight 655, as an attacking F-14 Tomcat fighter
  aircraft. The Iran Air Flight 655 was climbing at the time, and her
  IFF transponder was on the Mode III civilian code rather than on the
  purely military Mode II, as recorded by Vincennes's own shipboard
  Aegis Combat System. Vincennes fired two radar-guided missiles and
  shot down the Iranian civilian airliner over Iranian airspace in the
  Strait of Hormuz, killing all 290 passengers and crew on board.

Based on the narrative (and any other supportable information): Does the root cause of misidentification comprise:

Failure to follow procedure (Military / Civilian IFF, etc.)?
Equipment Failure?
Human factors (Fatigue)?

The questions are posed because this is the first of at least two Iranian-originating civilian flights that are misidentified by military personnel: I am wondering if there is a pattern, that can produce a lesson-learned (when the final report is published).

You have two data points, 30 years apart, whose only obvious commonality (beyond being accidental shoot-downs) is the county they both departed from. Essentially every other potentially relevant detail differs: nationality of the shooter & of the airliner, equipment shooting and being hit, and a plethora of differing circumstances. I doubt that parallels between these two incidents will be nearly as interesting as a detailed analysis of each one individually. Although, getting truthful, accurate details from Iran right now seems, um, challenging. "Scientific impossibility," right?

@RalphJ  There is a glimmer of hope that the data will be available: Today, the Iranian leaders have indicated that Iran owns the second data point.   I would like to see the international community work together and harvest lessons-learned

lack of research, and the mistaken belief that life in the 1980's was identical to life now.

tl;dr We don't know.
The US Government has not made enough information available to answer this question. The official Iranian and US reports contradict each other. Inofficial accounts of sailors on other USN vessels operating in the vicinity at the same time contradict both the official US report as well as statements made by Vincennes commanding officer.
There are several possible explanations, many of which have not been officially acknowledged, and probably, the real cause will be a combination of multiple factors. And some of those are easy to address:

User Interface Design: the target tracking system recycles target designations. Shortly before the shootdown, the system had assigned a new target designation to the aircraft and recycled the old designation for a fighter operating over 100 miles away. When the CO asked what the classification for the target designation was, the answer was "fighter" and that it was descending, which was correct for that target designation, but was actually for a completely different aircraft now.

Don't Do That!

No access to current flight plans: the crew only had access to the standard regular schedule, but not to updated flight plans, e.g. including delays or cancellations. On the day in question, the flight was delayed by over half an hour.

Assets used for monitoring mixed-use airspace should be equipped with civilian radios and be in contact with ATC.

Ergonomic Design: the lights were so dark, and flickered every time the weapons were fired, that the crew assigned to monitor the airspace couldn't read the printed out flight schedules.

Better lighting. Or, put the schedules / flight plans into the computer. Even better: integrate them into the target tracking system.

Timezone confusion: the flight schedules were printed out in Iranian time, but the ship's time was Bahrain.

One word: UTC.

Missing Equipment: the Vincennes had no possibility of using civilian frequencies (other than the international distress frequency 121.5), so they had no way of knowing that the "unresponsive" aircraft was in fact in constant communication with ATC.

See #2. Note that directly after the incident, the US Navy did install tunable VHF radio on all ships in the Gulf.

Wrong Frequency: of the 10 attempts to establish contact with the aircraft, 7 were made on military frequencies. Obviously, being a civilian aircraft, the Airbus had no way of hearing this.

Train crew to remember that failure to respond to a military frequency does not imply hostile intent, especially since civilian aircraft won't even be able to respond.

Speed confusion: when the Vincennes adressed the unidentified aircraft, they gave the aircraft's speed in groundspeed as 350kts, but the indicators in the aircraft would have read 300kts indicated airspeed. Since the speed was wrong, the pilots may have thought the calls were made to a different aircraft operating in the vicinity whose speed was closer to the one in the call.

Make it clear in your transmission that you are talking about groundspeed.

A year earlier, another USN vessel was (mistakenly) hit by Iraqi missiles. Her commanding officers received official Letters of Reprimand, effectively destroying their careers, stating that defense of the ship is the first duty. This may have put the CO under additional pressure, fearing for his and his family's livelihood.

Don't punish people for being hesitant in highly complex combat situations involving close proximity of civilians.

Scenario Fulfillment is a psychological condition affecting both individuals and groups where once a situation looks like a certain training scenario, that scenario will be followed to the end, filtering out all Information that does not fit the scenario. The US Government has put forth the possibility that the entire bridge crew may have collectively suffered from this condition.

Psychological training.

The crew was under stress since they had illegally and unprovoked entered Iranian waters, and were simultaneously also engaged in a firefight with Iranian gunboats (which Vincennes provoked by illegally sending her helicopters into Iranian airspace). Either of these two infractions would have been cause for Iran to send fighters to intercept and attack the ship.

See #9.

The CO was known to be a hot-headed aggressive guy looking for fights, and even creating them if there was none. He may have been looking too hard and found one where there was none.

Don't hire such guys, filter them out using psychological evaluations.

Your last paragraph is dead wrong. It would be a bit closer to correct to observe "don't promote such guys, filter them out"  and "improve command training" - it took roughly 20 years to get to even be eligible to a the captain of an Aegis cruiser, to include a previous command tour on a smaller combatant.  The rest of your answer is a good review of how that scenario is presented in officer training modules.  You also missed the critical factor: there was no Visual Identification, and since the Cruiser was not operating with a battlegroup, no airbore aircraft to send that way to get a VID.

On point 1, I read somewhere (got no source, though) that the radar operator had put the cursor over the plane on his screen before it left the airport, which assigned it a mixed civilian/military mode on IFF. After it took off a fighter taxied to the runway and since the cursor on the radar was still over the airport the readout changed to the military IFF squawk from it.


text:
What prevents miltiary jets and turbo-props from being refitted with a turbofan?
What prevents military jets and turbo-props (such as P-3 Orion) from being refitted with a high bypass turbofan?

They already did that with the P-3.  It's called a P-8 Poseidon.

Clarification: the P8 is NOT retrofitted with a turbofan.  The P8 airframe is designed to work only with a turbofan


text:
What are these "F,S,O" characteristic speeds?
I am leaning for an avionics exam and I encountered a question asking for the meaning of F, S and O . They appear to be "Characteristic speeds", which are calculated by the flight management system (FMS):

What's the context? Could you quote the entire question, for example?

I've never heard of the term in 20+ years in avionics. Closest thing I could relate it to would be the DME Free Scan Mode. Could they be referring to this as Free Scan Operation?

I found a slide in which $F, S, O$ appear. Maybe that help. It is right of $V1$ $VR$ and $V2$.

When asking this type of question you need to specify the context, ie the aircraft or manufacturer. In this case, you're talking about an Airbus. On the speed tape (on the PFD) there are various marking which refer to critical speeds that the pilot needs to know about - marked by the letters F, S and O. Airbus experts will chip in with the exact definitions of these speeds.

F speed is the minimum speed at which flaps should be retracted from CONF 3 or 2 to CONF 1+F.
S speed is the minimum slats retraction speed, i.e. the minimum speed at which a clean configuration should be selected.
GD speed is the engine-out operating speed in clean configuration. In other words, it corresponds to the speed that allows the highest climb gradient with one engine inoperative in clean configuration.

source:
https://www.icao.int/WACAF/Documents/Meetings/2015/ICAO-BEA/SafetyFirstissue20.pdf


text:
Does a safety pilot log PIC, or SIC?
I just got my private pilot license and I want to build-up time with another private pilot
lets say I am acting as a safety pilot and we make a flight of 3.7, and his time under the hood was 3.4 in C172
1-as a safety pilot, what is my total durain time?
2- as a safety pilot, am I going to log PIC, or SIC? and how much?
I keep getting different answers. It would be really appreciated if you cite your source.

@757toga That's a good point and I admit I didn't really take account of the SIC aspect. But my personal opinion is that we already have enough PIC/SIC/safety pilot logging questions here, so I followed ymb1's suggestion and added a new answer to the other question, that covers both PIC and SIC time (at least in the most common situation that everyone seems to ask about). If there's a better way to handle this then I'm absolutely open to it, of course.

@ymb1 FYI, see my comment to 757toga (can't tag more than one person in a comment!)

@ymb1 I didn't know (or just forgot) that merging is a thing, it seems like a good option to me in this case. There are other scenarios that are a bit trickier (as 757toga pointed out) but this specific question seems to me to be the most basic/common one and it matches the other question, IMO. So no disagreement :-)

@ymb1 Thanks for the update!

Assuming that you have a single-engine land certificate, you can log PIC time if, per §91.109

(c) No person may operate a civil aircraft in simulated instrument
  flight unless—
(1) The other control seat is occupied by a safety pilot who possesses
  at least:
(i) A private pilot certificate with category and class ratings
  appropriate to the aircraft being flown; or

You do not have to have endorsements for the particular aircraft e.g. high performance, or complex as long as you are rated in the category and class. FAA Legal Interpretation Herman - Logging PIC (2009)

Although these endorsements are required before a pilot may act as a
  PIC of a high-performance and/or complex airplane, they are not
  required to log PIC time if the pilot is rated for and is the sole
  manipulator of the controls of the aircraft.

You may not log SIC time since the aircraft type does not require a second pilot. FAA Legal Interpretation Beaty - (2013) SIC Safety Pilot

Because the aircraft is type certificated for a single pilot, and
  because the operation does not require a designated SIC (e.g. an
  operation conducted under 14 c.P.R. § 135.101 which requires an SIC
  under IFR), Pilot B is a safety pilot and not an SIC.

You may log SIC time, though I don’t know why you would want to. Legal Interpretation louis glenn - (2009)

When a pilot is operating an aircraft in simulated instrument flight,
  14 C.F.R. § 91.109(b), in relevant part, requires that a safety pilot,
  who possesses at least a private pilot certificate with category and
  class ratings appropriate to the aircraft, occupy the other control
  seat. Accordingly, Pilot B may log SIC time for the portion of the
  flight during which Pilot B acts as safety pilot because Pilot B was a
  required flight crewmember for that portion of the flight under § 91.1
  09(b). The FAA previously has interpreted that a person acting as
  safety pilot for a portion of a flight may not log cross-country time
  because that person is not a required flight crewmember for the entire
  flight.

You may not log cross-country time since you haven’t taken off and landed. FAA Legal Interpretation Gebhart - (2009) Safety Pilot

In your example, Pilot A may log the entire flight (2.2 hours) of PIC
  flight time because that pilot was the sole manipulator of the
  controls for the entire flight. Pilot B may log the portion of the
  flight during which Pilot A operated in simulated instrument flight
  and Pilot B acted as the safety pilot (2.0 hours) because Pilot B was
  a required flight crewmember for that portion of the flight under 14
  C.F.R. § 91.109(b).

Yes you can log time as safety pilot where you are taking legal responsibility for maintaining VFR separation during hood practice.  Otherwise it has to be a multi-crew situation by operating rules or due to the aircraft type.  This covers it pretty good.  https://www.aopa.org/training-and-safety/learn-to-fly/logging-cross-country-time/logbooks-and-logging-time

Can you edit this to point out that you can log PIC time for the time during which you're the actual PIC and the other pilot is "under the hood"? As it is, it sounds like you're saying that the safety pilot can never log PIC time, which isn't true.


text:
On an engine failure, can I contact the tower instead of 121.5?
Let's say I am cruising at a very high altitude with my Cessna, like at 5000ft+ AGL, and I got an engine failure.
After going through the checklist, my engine is still not working, but I realized that I could easily land the airplane on an airport near me with my gliding speed.
Can I just talk to the airport, whether controlled or uncontrolled and take whatever runway is best for landing, instead of declaring an emergency on 121.5 and squawk 7700?
Thanks.

Re "very high altitude with my Cessna, like at 5500 MSL": Did you mean AGL (Above Ground Level)? In much of the western US, 5500 ft MSL is pattern altitude, if not field elevation, or underground :-)

On the flip side of your question, if you are having trouble getting authorization to land in the way you need, I have heard that the act of declaring an emergency can release administrative red-tape and make it easier for ATC to authorize what needs to happen to get you on the ground safely.

@CortAmmon If you're in an emergency, you (the pilot) can do pretty much what you want to deal with the emergency in a safe and expedient manner, as long as you can reasonably justify the action you took. ATC basically cannot tell you "no" at that point, but you'll likely need to explain yourself once on the ground. US 14 CFR §91.3(b); EASA SERA 2010(a), 2015.

I'm basically going to echo what's already been said, but with a twist.
Yes, of course you can keep talking to the people you're already talking to, on the frequency you're already on. If you're actually talking to someone already, that's probably your best bet, not least because they know you're there.
In fact, especially if you're in controlled airspace, one might argue that speaking up on the radio immediately upon engine failure isn't a horrible idea, if and only if you are able to do so safely. Even a simple "Springfield tower, Cessna '345, pan-pan-pan, engine failure, attempting restart", maybe even while you're pulling out the in-flight engine failure checklist, will give ATC a heads-up that, at the very least, you won't be able to maintain altitude. That would allow them to take your situation into account when vectoring other traffic. If all they see is a VFR GA plane starting to descend, for all they know that's perfectly intentional maneuvering on your part.
Only if you can't reach anyone (who is able to help) on the frequency you're currently on does it make sense to consider fiddling with the radio to switch to 121.5. Fiddling with the radio to change frequency should be well down your mental list of actions to take.
The same reasoning applies to the transponder; you certainly can change to 7700 if you want to and you feel that it is appropriate, but you don't have to. Squawking 7700 will cause your radar return to light up like the proverbial christmas tree at ATC, but saying mayday or possibly declaring emergency is also a pretty good way to get peoples' attention in a hurry.
Once you realize that the engine isn't going to cooperate in restarting, and especially if you realize that you'll be able to make a controlled (but forced) landing on the nearby airport, I'd pretty much just treat it as an ordinary landing, with the caveat of declaring at least pan-pan-pan, possibly mayday, and telling ATC that you have no engine power. Let them deal with the other traffic and just focus on executing a safe landing and vacating the runway as quickly as you are able, but no quicker.
If you realize that the engine isn't going to cooperate, and that you can't make it to the nearest airport, well, that's when a forced outfield landing likely becomes a tempting option. Telling ATC (possibly on 121.5, with the above caveat on whether you're already talking to someone) what your position and intentions are will still allow them to get help out your way in case you do botch the landing. If you do make it down safely, be sure to tell them, relaying via another aircraft if necessary.
Aviate, Navigate, Communicate is a good rule of thumb, but it's a rule of thumb, not dogma. If you're able to communicate while still aviating and navigating, then doing so might help ease at least the burden of navigation.

Minor nitpick regarding the last sentence, that's exactly the point of "Aviate - Navigate - Communicate": do all of them if you can, but prioritize them as such. Task shedding (i.e., do the ones on the left even if it means you can no longer do the ones on the right) isn't a deviation from the "rule of thumb," it's the whole point. Otherwise +1!

@TypeIA Very possibly true, but in practice, I've seen a lot of cases where people don't treat it as such, but rather seem to more in terms of "don't communicate, just aviate and navigate", even when communicating could ease especially the burden of navigation. (As I'm sure you know, ATC can help with traffic advisories, vectoring, keeping an eye on your position, and lots of other stuff that will allow the individual pilot/s to spend more of their focus on the aviating. Heck, just asking for a straight-in approach vector and distance to the nearest airfield can nearly eliminate navigation.)

Major nitpick. The call is MAY-DAY MAY-DAY MAY-DAY Cessna '345, MAY-DAY MAY-DAY MAY-DAY Cessna '345, engine failure, attempting restart, will try to glide to Springfield 0-6. I would even argue that you should first pick a passable landing spot and then try to get the engine running again, because your options will be more limited after 2 minutes trying to restart with the 2,000 ft less. And if you do get the engine running, the emergency remains and you only change your course of action if you planned an off-field landing until now—the engine is not to be trusted at this point.

An urgency, PAN, is for cases like the tablet with your foreflight failing so now you have to fish out the paper map—things that increase your workload, but were not really needed. But failure of anything and everything that is actually required for flight always warrants an emergency, MAY-DAY, and failure to treat it so has killed a lot of people. Even if you don't call it on the radio, or before you do, think of it as an emergency, because that's what it is.

Also, it's aviate, navigate, communicate, and troubleshooting does not belong in either. Even troubleshooting a stopped engine does not.

In an emergency, such as an engine failure, the answer to "can I do X" is almost always a resounding "YES".
You can do anything within your power to protect the safety of those on board. That is your job as pilot in command. If you think it is safer to ask a controller to manoeuvre big jets out your way so you can touch down on an otherwise busy Airport, then you do it. If you see a farmer's strip that you can land on, you do it. You do whatever is necessary to safely bring that aircraft down.
Aviate. Then navigate. Then communicate.

"ask a controller to manoeuvre big jets out your way" - to clarify, he wouldn't need to ask that specifically. If someone has an emergency, we are going to move other traffic out of their way by default, no questions asked.

Yes, absolutely. In fact, the preferred and normal option is to talk to whoever it is you've been talking to previously. Whether that be a local tower or a regional RADAR operator.
121.5 is a frequency of last resort, and acts as an emergency fallback and catch-all.
Ultimately, you're in charge of your emergency and you make the decisions. Do you have time to mess with the radio - remember where "communicate" comes in the Holy Trinity.
That said, you should consider the advantages of talking to different people - what is making a May Day on an uncontrolled, potentially unmonitored frequency going to achieve? IF somebody is listening they MAY be able to relay a message for you but they're unlikely to be prepared to ready emergency services or search and rescue. Talking to a proper Air Traffic Service Unit is by far preferred, but it certainly doesn't need to be on 121.5.


text:
Why is the "wind triangle" an instructional method for solving Wind Correction Angle problems?
When solving a wind correction problem, what are the benefits of graphing wind speed/direction, true course, and true airspeed? Any digital calculator would be quicker; even the E6B would be faster (given that one is proficient).
I feel the graph method helps develop, over time, a better situational awareness when dealing with all sorts of crosswind problems and solving those problems on a "gut level."
However, for some reason, it sounds too simple to be the "proper" explanation from a pedagogical perspective.
Edit:
Changed "But this sounds like hardly the "proper" reason for using graphs." to
"However, for some reason, it sounds too simple to be the "proper" explanation from a pedagogical perspective.
"

Why do we still teach math in school when we have calculators that can do it for us?

I'm not sure what more you can expect from an answer than your second paragraph... (removing the frankly quite depressing last sentence - if wanting to understand things is no longer a "proper" reason to do things, what are we even doing here?)

Well, the E6b is a graphical method of solving the crosswind problem, right?  It's just handy way to draw the wind triangle, right?  You just aren't physically including the full lengths of all the arrows.

@Sanchises, I just had to ask myself if the answer is that simple? The question touches on best practices of teaching subjects like physics, and come to think of it, a CFI is also a science teacher. So I stopped and wondered, "Why the graph?" End I revised the last sentence as well. The original one was pretty grim.

@quietflyer, yes, the E6b is on the graphical side. I just find it difficult to look at the gray pencil marks on the rotating disc. And it's not as obvious as a drown out graph.

Because you need to make sure that you understand the concepts of what’s going on. It’s true that the digital calculator or digital East 6B can solve those problems for you, but that makes you susceptible to GIGO or Garbage In = Garbage Out. It’s very easy to make mistakes and erroneous calculations if you don’t understand what you are entering and if you don’t know what to expect from it.
Vector graphs are an excellent mathematical tool for visualizing what’s going on and how an aircraft’s flight path is affected by winds aloft.  You are correct that’s it’s not practical to perform this in the cockpit of an airplane while flying, but performing this on the ground gives you a much better sense of how winds affect you so you can use this to assess answers generated by
As an example, suppose you want to fly a true course of 280°.  The local winds at altitude are 210° True at 13 knots.  Your airplane flies at 150 KTAS.  By the numbers you’ll notice that we’ll have a light to moderate crosswind with a slight headwind component.  Using some basic judgment we estimate we should see a heading of ~3-5° short of our intended course and maybe ~5-10 kts slower groundspeed.
And in fact, if we compute this on an E6B, we find a desired heading of 275° True, with a WCA of -5°, and a groundspeed of 145 knots.  That seems pretty close to what we anticipated, so we can use our knowledge of wind correction and effects to conclude that the calculation we performed in the answers we got are accurate.

...and you only know those approximations because you've visualised it previously on an E6B or similar. If you've only ever plugged the numbers into a digital tool of some sort you have no idea what it's supposed to be. So you can't "sense check" it.

Because if you don't provide explanations like this (Why does the airplane not 'feel' the crosswind?), then people will be left with misunderstandings like this (Why does the airplane not 'feel' the crosswind?).
Because vector diagrams are very simple and easy to understand, and are at the heart of the basic physics of motion, which is highly relevant to flight.  Same reason we expect every pilot to be able to draw the basic Lift-Drag-Thrust-Weight diagram for level flight, gliding flight, climbing flight, etc.  If they couldn't draw those diagrams correctly, they'd be in danger of crashing.
Or at the very least, they'd be robbed of the chance to  understand and appreciate one aspect of the beauty of flight.


text:
Where can I find Take off and Landing Zones for GIS Integration?
I am a GIS specialist and looking to plot the take off and landing zones into major and minor airports across the UK. This is dominantly to see land affected by noise pollution from air traffic. If data exists for private airfields as well that will be a bonus.
High altitude flight paths data such as this website is not necessary as I simply require the bearing of take off and landing zones into airports to an altitude of ~3280 ft. The referenced website download file formats are not exactly GIS friendly and the option to batch download multiple files does not exist.
File formats I'm looking for are either shapefile, gpkg, kml (google earth) or GeoJSON and a batch download for all landing and take off zones will be desirable.

are you looking for IFR, VFR or both?

If you don't get an answer here, you might try [opendata.se].

You mean runways?


text:
Can an empty 747-400 with minimal fuel take off on two engines?
This is a fanciful question. 747s are allowed to take off on 3 engines for maintenance ferries (I did a couple), but a 2 engine takeoff is not a practical or legal consideration. However, my gut level feeling is that it could be done in optimal conditions, but I'm interested in what the more technically oriented people here have to say.
The aircraft for this thought experiment is a 747-400ERF, a freighter with a basic operating weight of 351,088 lbs and a max takeoff weight of 910,000 lbs. Let's say we want to take off and make a 15 minute swing about the countryside around Moses Lake, WA with its 13,500 runway, elevation 1189 feet, on a STP day with no wind. It's flat land, there are no departure or arrival path obstacles.
We want to land with no less than 15,000 lbs of fuel, and the takeoff and flying is going to take around 20,000 lbs. Thus our takeoff weight is going to be around 386,000 lbs, which is roughly 42% of the max takeoff weight.
We have half our engines inoperative, but we are significantly less than half as heavy as the max takeoff weight. To make it easy, let's say that engines 2 and 3 are operating (the inner most engines on each side).
So, what say you?

Cool thought experiment! I'm assuming you don't need to be able to satisfy usual "V1 cut" performance requirements? (Of course, maybe if you had two of those monster GE-90-115b's...)

Hmm... I guess this will come down to how much of the drag is induced drag vs. how much is form drag. The induced drag will obviously be much less, but the form drag will not be much less than flying at the same airspeed at MTOW.
Given the requirement that it must be capable of continuing a takeoff and climbing out at MTOW on 3 engines, though, I'd be very surprised if it weren't capable of doing so at 42% MTOW on 2 engines.
For the most convincing argument in favor of 'yes' I can think of off hand, there's this. GE flew a 747 on one engine. Granted, that engine happened to be a GE90-115b, the world's most powerful commercial jet engine, which is used on the 777-300ER. However, the GE90-115b is rated at 'only' 115,300 lb. of thrust, while a pair of PW 4062s on a 747-400ERF would produce a total of 126,600 lb. GE's aircraft is a modified 747-100. Since Wikipedia lists its operating empty weight at 358,000 lb. and it was hopefully carrying some fuel in addition to that, its weight was likely not much different from the 386,000 lb. in your scenario. Additionally, in GE's case, some of the lift would have to be used to pull against the yawing moment created by flying with only the #2 engine producing thrust.
In light of this, I'd say that the answer is almost certainly, yes, it's possible. Advisable, of course, is a different matter entirely.

GE's Test Bed 747-100 with the GE90-115b mounted in place of its #2 engine. Source: Wikipedia

That's a phenomenal picture showing just how huge engines have gotten in the last 40-50 years!

@FreeMan Yeah, I've always liked that picture, especially when you compare the GE90 to the JT9D beside it and the humans walking on the ramp. Another one of my favorites is this one with a 777-300ER following a 737-800. The GE90s on the 777 are almost the same diameter as the fuselage on the 737.

I just noticed that the FlightGlobal blogs (where your image links) are now gone. If you happen to have another source for that image, it would be nice to post it.

@FreeMan Sadly, I don't. IIRC, it was copyrighted, so I never uploaded it to the SE imgur.

@FreeMan A notification reminded me of this post. Apparently when I responded to you before, I wasn't thinking about the obvious solution: working Wayback Machine link here.

I'm not sure if its possible, but I'll try to arrive at a conclusion by using the following mathematical model. Correct me if I'm wrong :
Lets assume all the four engines are operative at 80 p.c. of their full thrust
when they need to take of with MTOW.

So, for MTOW = 910,000 lbs,
if the plane is using PW4062, thrust generated per engine is 63,300 lbf
Net thrust T = 63,300*4*0.8 = 202560 lbf (At 80p.c. of full thrust)

Now, for MTOW, Normal Reaction N of the plane = 29120000 lbf
If, f is the friction force acting on the plane while takeoff, then

T - f = MTOW*(acceleration)
acceleration = (T - f)/MTOW   -(1)

for taking off with two engines and lesser weight, if the plane is able to
achieve the above mentioned acceleration, we can safely assume that it should fly.

so, acceleration in case of using only two engines (at 80 p.c. thrust) and lower weight is:

acceleration = (T' - f')/Weight   -(2)
Now T = 202560lbf
    T'= 101280lbf
    f = (u)*910,000lbf
    f'= (u)*386,000lbf
weight= 386,000lbf
MTOW  = 910,000lbf

from our assumption, lets equate 1 and 2 (and we'll use some constant k to be used later)

so, k(T-f)/MTOW = (T'-f')/weight
    k(202560-u*910,000)/910,000 = (101280 - u*386,000)/386,000
    202560*k - u*910,000*k = 238768 - u*910,000
    k = (238768 - u*910,000)/(202560 - u*910,000)

    Now, for u not belonging to the interval (0.222,0.262), k is +ve
    and for slip ratio (0,1) , u rarely exceeds 0.5

    hence, for k > 0.8, u lies in (0,0.22), which is quite possible.

Hence, acc. to this model, for a coefficient of friction of about 0.23 or below, its possible for an airplane to achieve the velocity required to produce the lift equivalent to the lift required to takeoff with MTOW. If this is possible, then generating the lift required to take off with lesser weight is also possible, theoretically.
p.s.
Sorry for some liberal assumptions I made in the model. Please correct me if I was wrong anywhere.


text:
Can both AC ground and DC ground connect to the same Ground STUD
Can both AC ground and DC ground connect to the same Ground STUD in a plane?

what kind of planes are you interested in?

It looks like you're asking whether when you need to connect AC and DC generators to the ground you can use the same stud. But as you know all studs are already connected by the aircraft frame and are equipotential (ignoring frame impedance). So I'm wondering if you're asking something else, e.g. if you need to connect both AC and DC to the ground, or if this is mechanically safe. It's not clear.

I am assuming you are referring to whether or not it is acceptable to connect the ground side of an AC supply and a DC supply to a common ground stud on the airframe. According to the FAA's Aircraft Electrical Wiring Interconnect System job aid, revision 2.0, page 116(PDF):

Grounding types: AC returns, DC returns, and others.
Mixing return currents. If wires carrying return currents from  different types of sources, such as signals or DC and AC generators, are connected to the same  ground point or have a common connection in the return  paths, an interaction of  the currents will occur.  This interaction may not be a problem, or it could be a major non-repeatable anomaly. Emphasis added.
• To minimize the interaction between various return  currents, different types of grounds should  be identified and used.  As a minimum, the design should use  three ground types:  (1) AC returns, (2) DC returns, and (3) all others.
• For distributed power systems, the power return point for an alternative power source would be separated.

Good practise advices to avoid mixing AC and DC returns in order to do not have noise coupling which can be dangerous for digital systems.
Keep in mind that EMI problems linked to system's power wire can be reduced by locating the power return near the aircraft circuit braker panel (twisting positive and negative wires can help too).

If you put your grounds together, and you have gnd and neutral reversed at a plug in the 120/240 side,  Inverter will see a dead short and fry MOFSET's. I just fried 2 inverters doing it. DC does not need an earth ground except to the case ground lug on the inverter.
I had AC/DC using a common ground spike. 120v sockets were wired with N and Gnd wired wrong. System was fine until I united the gnd's. 40a DC Fuses blew and 30a
120 breaker tripped on breaker panel. Inverter has dead short and MOFSET'S overheated cracking the insulator on some, others had discoloration at solder joints and circuit board traces @ source and drain.

is this answer for a house or an aircraft, which do not normally have a ground spike?

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.


text:
Can I fly this six motor drone?
My body weight; 70kg,
Drone weight; 50kg,
Props length 0.7m,
6 motors (2hp each),
Total weight 120kg,
Total horsepower 12,
Each motor runs 3000rpm,
Please can I fly it.
Thanks!!!
drawing of the drone

Are you asking our permission or whether it'll fly?

What have you tried so far to get these numbers?

@Jamiec  he is asking whether. If he was asking permission it would have been "May I fly this six motor drone" ;-)

Welcome to AviationStackExchange. You may notice that this site is specifically set up for very detailed and defined questions to get factual and verifiable answers. If you want to get an answer and not risk your question being closed due to it being too general, make your question as detailed as possible. Include any work and research you have done so far as well as what issue you are having in finding the answer yourself. Including what area or jurisdiction the question pertains to will also help.

Also, if you are asking whether you can fly any drone as the onboard pilot in command, the answer is no in the US. By classification, a manned drone is no longer a drone. Although, it may be considered an ultralight aerial vehicle if you keep its empty weight under 254 pounds, its top speed under 55 knots, and its fuel capacity under 5 gallons. In hat case, yes. Just as long as you stick to the rules of Title 14 of the Code of Federal Regulations Part 103.

@Jamiec may he is asking us how does he can work that

If your question is specifically about a small unmanned aerial vehicle with no humans onboard being flown by a remote pilot, please visit the Drone and Model Airplane Stack Exchange.

This is a classic case of "if you have to ask, the answer is a firm NO!"  People actually in a position to design larger than featherweight aircraft, regardless if they will carry humans or not, are people who know what they are doing, which is to say they do not post newbie questions critically short of detail.  There's far more to flying than opposing the force of gravity with a lift mechanism.

And don't forget to send it to us

Crucially: does prop length refer to the length of a single blade or the prop disc diameter?

Does rapidly rising off the ground and then quickly tumbling out of control until it violently impacts terra-firma, endangering any people nearby, count as "flying"? Because that seems like an entirely likely outcome here. "Well, it flew... right up until the loss of control, the crash, the explosion, and the fire. But for 1.2 seconds, it was, in fact, flying."

12hp isn't enough to lift a person like this, it's low for a paramotor and they have a huge wing. If you look at any of the man-carrying multirotors, they have much more power. Colin Furze's hoverbike had about 50bhp and barely flew, DCL's Big Drone is 217bhp - https://dcl.aero/explore/big-drone/

@Alberto L. Bonfiglio he did say "please," though, which sounds like asking permission.

No, you may not fly this drone. It weighs much more than 55 lbs. At least in the United States, you have to have an FAA clearance and hold an FAA Part 107 Certificate to operate anything that heavy.

Excellent answer to a question in dire need of a reality check! Welcome to Av.SE, and please come back often!


text:
How do I make a simple model to simulate a banked turn?
I'm attempting to make a game similar to Ace Combat, and I'm still confused about banked turns, namely the speed of bank turning depending on the aircraft's roll.
Can I assume, for simplicity's sake, that it's something like $Rgy = K * Rz$, where $Rgy$ is the rate of turning on the global Y axis (the banked turn's angular speed), $Rz$ is the roll angle of the aircraft, and $K$ is a constant? And if I can do so, how do I calculate $K$?

It's computed with centripetal force:
$$F_C = m \cdot V \cdot \omega $$

m = aircraft mass [kg]
V = aircraft speed [m/s]
$\omega$ = rate of turn [rad/s]

Centripetal force is a function of bank angle $\Phi$ and lift, or mass and flight path. For a coordinated, level turn:

Vertical lift $L \cdot cos(\Phi)= m \cdot g$ and turning lift $L \cdot sin(\Phi) = F_C$, so in a steady turn
$$ F_C = m \cdot g \cdot tan(\Phi)$$
$$\omega = \frac{g}{V} \cdot tan (\Phi) \tag{Steady Turn}$$
A more general equation, also valid for 90 degree bank angles and not concerned with the aircraft staying up in the air, can be found by considering horizontal forces only:
$$ \omega = \frac {L \cdot sin(\Phi)}{m \cdot V} \tag{always} $$
And then if you assume that lift L is still equal to weight $m \cdot g$ which means the aircraft is losing altitude in this turn, you're almost back at the Steady Turn equation but now with a sin instead of a tan.
The above is for SI units. For aircraft units with feet and knots, please check this answer, and here is one that introduces lift coefficient into the equation.

Thank you. Though if Φ is 90 degrees, won't ω be infinite, since tand(90) is +/-infinity?

@Gensoukyou1337 It would, but you can't fly stationary turns at high bank angles. The aircraft would break apart

@Gensoukyou1337 Yes the equation is only valid for steady turns where the vertical component of the wing lift still compensates for weight. At 90 degrees there is no such component. A fighter jet might use thrust in a 90 deg turn, point the nose angled upwards while flying on its side, using fuselage lift as well. $F_C$ would be provided by all of the wing lift in that case. A more generic equation would use $L \cdot sin(\Phi)$ for the centripetal force.


text:
How to calculate the minimum possible flight speed of an aircraft?
So for the minimum possible flight speed an aircraft can fly with for a given altitude, I just use
Lift=Weight  and solve for the velocity.
But: I need to insert a lift coefficient, which I can get from airfoil + body data table.
Lift coefficient depends on the angle of attack. Up to stall, the lift coefficient increases with angle of attack.
I have my highest lift coefficient for an angle of attack of alpha=24°
So my question: does it make sense to choose this lift coefficient?
Because: the higher my angle of attack, the less thrust of my jet engine is there to counterbalance the drag component, so I will have to give more thrust (because only the cos(alpha) component can be used of the thrust vector).
So in the end, I could use my highest angle of attack and reduce flight velocity, as long as I have enough thrust to counterbalance the drag component, is this correct?
If yes, are there any limitations as long as I do not have a stall?

You seem to have an understanding of the basic variables at play-- I'm trying to figure exactly what the question is--

Re "so I will have to give more thrust (because only the cos(alpha) component can be used of the thrust vector"-- this is a true statement, but, of course, the cos (alpha) issue which affects the available thrust (measured along the flight path axis) is not the only reason that you need more thrust (measured along the engine axis) when you are flying deep on the backside of the thrust-required curve, than when you are flying at the max L/D speed!

It looks like you have created multiple accounts. Be aware that you won't be able to fully participate to the site if you don't gather enough reputation. It is easier to do so by having one single registered account: https://aviation.stackexchange.com/help/merging-accounts

You are right that cos(alpha) reduces the thrust component counteracting drag (assuming that the thrust line is along the average chord line, which defines angle of attack alpha). But did you also consider that sin(alpha) now acts along the lift direction?


text:
What happens if I am flying at a higher Lift/Drag ratio than required?
I created for me a table from an aircraft for Mach=0.8 for alpha= 0° to 8°
Actually, I an alpha of alpha=4° should be sufficient, so that my lift coefficient is enough, to counterbalance the weight in steady horizontal flight. The corresponding lift/drag ratio is 8.
I could now choose also alpha=8° , with a lift/drag ratio of 12.
My question: regarding the range equation(breguet) it is better to have a higher lift-drag ratio for making more range.
But I am wondering: if I choose alpha=8° my lift coefficient is greater than the one I need, so in the end, my aircraft will climb ? This would not be a steady horizontal flight.
Am I right?

You used the term "I am flying" to describe this airplane.  I'm just curious, do you own or even fly an aircraft that cruises at mach 0.8?  I'm just wondering because it is worded as if you are the pilot, but it is difficult for me to understand from a practical standpoint what you are asking if that is the case.

If your optimal lift coefficient for long range cruise flight is greater than what you need, you are flying too fast, or too low.
For cruise flight, your lift needs to equal the weight, otherwise the aircraft will accelerate upwards (in the body frame of reference).
If you know the lift coefficient that is optimal for cruise, you need to adjust the airspeed and density (altitude) to make sure that the resulting lift equals the weight.
$W = L = \frac{1}{2}\rho V^2 C_L S $
$\rho V^2 = \frac{2 W}{C_LS}$
Reduce speed and/or increase altitude until the lift and weight are equal at the optimal lift coefficient. That will give you the maximum range.

Or maybe you're flying too low?

@Abdullah or in too cold air...

This related ASE answer may help -- "Does Lift equal Weight in a climb?". Note that a steady-state climb is associated with a smaller lift force than level flight, not a larger lift force. On the other hand, a loop is associated with a larger lift force than level flight.
If you increase the lift coefficient, you've increased the lift force -- if you keep airspeed constant.  Since Mach is constant, and therefore airspeed is constant, it appears that your question is overly constrained.  Not all your parameters can be met simultaneously if the flight path is to remain horizontal.  In a particular aircraft in a particular configuration, only one value of the lift coefficient is consistent with horizontal flight at a particular indicated airspeed.
(Note-- actually we can decrease the indicated airspeed while holding the Mach constant, by choosing a higher cruising altitude.  Since your question doesn't specify any particular altitude, this would appear to be a valid solution to your problem.)
On the other hand, if the altitude and Mach number are both constrained, constraining the indicated airspeed and giving "too much" lift at the optimal L/D ratio, and this is a design exercise, with the shape of the aircraft not yet "frozen", you could solve the "excess lift" problem by decreasing the wing area, allowing the aircraft to cruise at the optimal L/D ratio at the target airspeed and altitude.

great answer quiet flyer!